Apparatus for making toothed gearing.



P. HU MPHRIS.

APPARATUS FOR MAKING TOO'I'HED HEARING.

APPLICATION FILED JUNE-18,1910,

1,040,6843 Patented Oct. 8, 1912.

F'- M a SHEETSSHEET 1. @111 ummk\\m\\m nmmnuunuanmnunnmmm F. HUMPHRIS.

APPARATUS FOR MAKING TOOTHED GEARING.

APPLICATION rum) JUNE 18, 1910.

1,040,6M. Patented 0013.8, 1912.

3 8HBETSSHIJET 2.

P. HUMPHRIS.

APPARATUS FOR MAKING TOOTHED GEARING.

APPLIGATION IILED JUNE 18, 1910.

1,040,68%. Patented 001;. s, 1912.

3 SHEETS--SHEBT 3.

FRANK HUMPHRIS, OF BARTON PEVERIL,

EASTLEIGH, ENGLAND, ASSIGNOR TO THE HUMPI-IRIS ENGINEERING SYNDICATE LIMITED, OF LONDON, ENGLAND.

,APIARATUS roe MAKINGTOOTHED GEARING.

Specification of Letters Patent.

Patented Oct. 8, 1912.

Application filed June 18, 1910. Serial No. 567,582.

To all whom it may concern:

Be it known that I, FRANK HUMrnRIs, a subject of the King of Great Britain, and residentiflof Barton Peveril, Eastleigh, in the county of Hampshire, England, engineer,'have.invented' certain new and useful Ap'paratusfor Making Toothed Gearing, of Wh'i'chthe following is a specification.

This invention relates to 'appari'itus for producing the operative surfaces of the socalled generated motion-transmitting elements in gearing wherein the operative surface 013a motion transmitting element in one member is produced by the generative action of a rotary cutter having an el'l'ective profile which represents the operative surface of the coacti'ng 'element 1n the other member of the gear-in The invention relates more particularly to generating apparatus for use in' the production of the operative surfaces of the helmet shaped teeth and correspondingly shaped recesses or holes constituting the generated elements in the well-known Humphris type of gearing described and illustrated in United States Patent No. 859,662 dated July 9, 1907 ,and United States pending application' Serial No. 467,154.

The invention consists in the combination with means whereby the entire movement feed movement) between the work and the -c'utter, each regarded as a whole, may be produced in a direction corresponding to that of the perpendicular to the common tangent to the pitclrlines of both members of the gearing. The invention is thus distinguished from generative apparatus for use in the reduction of. the operative surfaces of motion-transmitting elements in gearing of other kinds than those referred to above, and wherein a rotary cutter representing the operative surface of a motion-transmitting element in one member of the gearing is employed to generate the operative surface of the coacting element in theother member of thegearing; inasmuch as, although in some cases it has been proposed to communicate 'ieither to the workalone, or to the cutter alone, the entire movement required to pro-- lduce an effect equivalent to that of the proper relative motion at the predetermined vclocity-ratio between the respective memhers of the gearing, no provision has heretofore been made for producing further relative movement between the work and the cutter in a direction corresponding to thatof the perpendicular to the common tangent to the pitchdines of both members-of the gearmg.

f In the case of gearing of the Humphris Itype, wherein the motion-transmittin (316-: ,ments are constituted by helmet-s aped :teeth and correspondingly shaped recesses or holes on the respective members, and more especially in cases where (as in the jpreferrcd form of said type of gearing) the maximum thickness of each tooth and the minimum thickness of the material whichseparates two adjacent holes, measured on the pitch-lines of the'respective members of ;the gearing, is approximately 0.7 and 0.3 of the pitch respectively, it is necessary to provide means for producing (as above set forth) relative movement between the work }and the cutter, each regarded as a whole, in a direction corresponding to that of'the perpendicular to the common tangent to the piteh-linesof both members of the gearing, for the reason that, owing to the excessive (although varying) amount of strain, not directly balanced, to which (hiring the gencrating operation the cutter is subjected in directions not coincident with its axis of ro tation, it is found impracticable to produce on the work a complete surface presenting the true generated configuration unless; the total depth of cut is performed in progressive stages, the depth of mutual engage, ment between the work and the cutter being gradilally increased at successive traversing movements of the work and cutter relatively to one another, from a minimum to the max imum required. Generating apparatus constructed inmcmrduuce with the present in-;

,sions.

Gil

In the accompanying drawings which represent (in a somewhat elementary form) certain typical embodiments of the invention, Figure l is a plan View and Fig. 2 is a side elevation of mechanism for generating teeth or holes in the periphery of either member f a pair of spur-wheels (2'. 6. gear wheels rotatable in the same plane with. one another), the gearing being external. Fig. 3 is a sectional side elevation, and Figs. 4 and 5 are plan views taken respectively ,on lines 4-4 and 55 of Fig. 3, showing a modified form of generating mechanism for use in the production of external spurwheels.

In the drawings, parts of the mechanism which perform corresponding functions are, in general, denoted by the same or similar reference symbols.

Referring first to the mechanism illustrated in Figs. 1 and 2, which is adapted tr generate teeth or holes in the periphery of either member of a pair of external spurwheels; A represents the cutter which is caused to rotate about its axis of symmetry aa by being mounted in a tool-holder on the end of a horizontal spindle which may be driven and controlled in any convenient manner such for example as that employed in ordinary milling machines. The rough wheel or blank B is mounted to rotate in a horizontal plane so that the axis a-a of the cutter shall lie in the plane of rotation of the wheel, the blank being carried by the intermittently-rotatable upper member 0 of a dividing-head 0 adapted to enable the blank to be turned about its own vertical axis b-b, between successive generating operations, through an angle equal to that separating the adjacent teeth or holes to .be produced, and to be locked, between these successive turning movements, against such rotation about its own axis.

The dividing-head C is mounted on a carrier D which is adapted to receive such angular motion, in a plane parallel to the plane of rotation of the blank B, as will truly represent that absolute motion of the axis 6-!) of the blank which is the equivalent of the true relative motion between the axes of the two members of the gearing whereof the wheel produced from the blank is to constitute one; this angular motion of the carrier D being performed about a stationary axis ee constituted by a vertical gudgeon E mounted upon or engaging with some fixed portion F of the machine. The

.axis ee, which represents the axis of the other member of the gearing, is parallel to the axis bb of the blank and intersects the axis a-a of the cutter at a distance from the point thereof equal to the corresponding radius of the wheel whereof the cutter A represents one hole (or tooth).

The dividing-head C, to which the blank is mounted; while means are provided forgiving to the dividing-head O the requisite.

rotary movement about the spindle C at the proper velocity-ratio, during the generating operation. For this urpose the arrangement illustrated comprises a toothed circular lower member .0 of the dividing-head O and having a pitch-radius equal to that of the wheel to be produced from the'blank,

and a second toothed segment H in gear with the first, fixedly mounted concentrically with the axis e-e about which the whole carrier D is movable, and having a pitch-radius eqp'al to that of the wheel with which the w eel to be produced is required to work in gear. With such a construction it will be seen that, when the carrier D is oscillated about its stationary axis ee, the blank B will not only move bodily with reference to the cutter A (the axis b,-b of the blank passing to and fro across the axis arr-a of the cutter prolonged), but will also rotate in. the corresponding direction about its own axis bb along with the dividing-head C, with the result that (assuming the amplitude of the oscillation to be sufficient) the segment G fixed to and concentric with the 1 tooth X (or hole) produced on the blank B by the cutter A will display the characteristic shape required.

In order to accommodate blanks of diiferf ent diameters, the dividing-head C may be mounted on the carrier D not directly, but

through the medium of a slide-block J withv reference to which the dividing-head is to tatable, this slide-block, which carries the spindle 0 being adjustable on guides j which extend parallel to a line drawn through the stationary axis e-e of ,the carrier and the axis bZ of the dividing-head and blank so that the distance between'the'se axes may be varied as required.

The carrier D, which is supported by a fixed segmental guide K concentric with the axis c--e, may be moved about said axis by any convenient means, such for example as a tangent-screw K engaging a nut 70 attached to the carrier.

In place of the two toothed segments G and H above described, plain circular seg ments, having radii respectively equivalent to those of the toothed segments, may be employed, the periphery of that plain segment (corresponding to G) which is fixed to the dividing-head C rolling in frictional contactwith the periphery of the stationary segment corresponding to H). construction, provision must be made for maintaining such ,tfrictional contact between In this 'means of a flexible but inextensible connection or connections lapped about their re spectrve surfaces. 1

Figs. 3 to 5, show a convenient construe.

tion suited for the production of external spur-gearing of a smaller size than that for which the mechanism illustrated in Figs. 1 and 2 is more especially desi ned.

In Figs. 3, 4 and 5 the stationary cutter A is rotated about its horizontal axis of symmetry a-a by any convenient means, while the blank wheel B is carried by the upper and intermittentlyrotatable member a of a dividing-head U as before. 1 he blank 13, during each generating o 'ieratiom is rotated along with the dividinghcad C about the common vertical axis Z -b of both, at the proper velocity-ratio, while said axis is at the same time caused to move across the axis a--a through an angle equal to that between two teeth or holes to be produced in the blank, this angular movement taking place about a stationary vertical gudgeon l0 Whose axis c-e represents that of the wheel whereof the cutter A constitutes the equivalent of one tooth or hole. For this purpose there is rotatably mounted on the fixed gudgeon E, a carrier 1) constituted by a radiusarm whereon the dividing-hcad G is supported, the lower member 0 of the dividing head being fast on a central vertical spindle C which is journaled in a bearing prm ided in a block J whose distance from the gudgeon E is adjustable (by movement in a slot 7' on the radius-ar1n D) to agree with the distance apart of the axes b--Zi and 4) representing the of the respective menu bers of the gearing. Fast on the lower end of the spindle (lf is a plain circular ment G whose radius is equal to that ol' the pitch-circle of the blank li and whose operative surface rolls in frictional contact with that of another plain circular segment ll fixed concentrically with the gudgeon l) and having a radius equal to that of the pitchcircle of the wheel whereof the cutter represents one hole (or tooth) the line of mutual contact between the segments G and ll lying in the common plane of the axes Z)-?) and a e, and being situated between said axes.

The requisite frictional contact between the rolling surfaces of the segments ti and H is insured by means of a flexible metal band L which on the one hand is lapped about a plain segment G", coni 'ilementary (as regards angular extent and position) to tie segment G and of equal radius therewith but situated in a plane out of the common plane of the segments G and I'l the about a ring H which is mounted bracing that portion of the ring band L embracing that portion of the segment (it which is remote from the axis e -e. The band L on the other hand is lapped to rotate (preferably on ball-bearings h as indicated) about the axis e--c, the band L em- 11 which is remote from the axis b-b.

For the purpose of maintaining the requisite tension in the band l, its opposed ends are shown as adjustab y drawn together by means of set-screws Z, Z, entering tapped holes in a block L fixed to and projecting from the periphery of the segment ll; while the effect of the positive engagement thus (in addition to the frictional contact) established between the band L and segment ll, is reinforced by means of a stud Z attached to the band and entering a recess in the segment G the stud Z and block L being situated at the sides of the respective segments which are remote from one another.

The gudgeon 15,, whose axis e-e intersects the axis a--a of the cutter A, is adjustable along the latter axis for the purpose of enabling the distance of the axis e e from the end of thc'cuttcr A to be varied to agree with the radius of the wheel whereof the cutter represents one hole (or tooth). For this ur ose"the gudgcon E is shown as mounted in a block E adjustable on a horizontal guide a proyidcd in a table I? which in turn is vertically adjustable upon a fixed part I? of the machine.

The machines above specified are only described by way of example, and it will be obvious that their arrangement and 'construction may be considerably varied in detail provided the result aimed at remains the same in each case. It will moreover be evident that by the employment of devices whereby the direction of the bodily movement of the work/and cutter relatively to one another is made rectilinear instead of rotary, machines (otherwise similar to those described) can be designed for the production of raclc-and-pinion gearing according to the same general system of generation which has been specified with regard to the forms of the miluall y coacting surfaces of the teeth and holesin the respective members of the gearing.

Having now particularly described and ascertained the nature of the said invention and in what manner the same is to be perwhich represents the operative surface of the coactmg element in the other member of the gearing, the combination with means for communicating to one of the said members,the entire movement required to pro-v duce an effect equivalent to that of the proper relative motion with the predeter- Joined velocity ratio between the respective members of the gearing, each regarded as a whole of means whereby further relative movement between the work and the cutter,

each regarded as a whole, may be produced in a direction corresponding to that of the perpendicular to the common tangent plane to the pitch surfaces of both members of the gearing, the common axis of symmetry and of rotation of the cutter being also perpendicular to said common tangent plane when the prolongation of said common axis intersects the axis of rotation of the Work, substantially as set forth.

2 ln apparatus for producing the operative surface of a motion transmitting element in one member of peg and hole external spur gearing by the generative action of a rotary cutter having an effective profile oa -sea which represents the operative surface of the coacting element in the other member of the gearing, the combination with means for communicating to the Work alone, the entire movement required to produce an efi'ect equivalent to that of the proper relative motion with the predetermined velocity ratio 

